Both of mine shot great from the start. The first was a 24" 6.5 twist shilen and it loves federal GM 90s, the Hornady 88s were MOA on average, not what I call good.
My best loads for the rifle is with 95 SMKs , Reloader 17 and Winchester 760. The group with RL 17 is six shots, after I chummed one high I had to send another, the win 760 is five. I've gotten first round hits on Praire dogs out to 750 yards with this combo and some steel plates shooting past 1000.
The last Valkyrie I put together I used a 18.5" 1-7" twist carbon fiber BSF barrel for a light weight coyote rifle.
After a 20 shot clean and shoot break in, it was smoking the factory federal 60s ballistic tips, sub 1/2 moa. This barrel also doesn't like factory hornady 88s, but shoots the 90s in the 3/4" range.
I probably won't bother working up a load for the 18.5" since I just use it for day hunting, sometimes at night with PVS-30 . I'm just going to get a case of the federal 60s.
I actually drew first blood with it last week. Called in a nice plump female coyote and drilled her with factory Hornady black 75 BTHP and she dropped on the spot.
Ive had good luck with the round so far and found it easy to load for with several different powders. I also know all ammo lots are not created equil. I noticed some lot #s shot better than others with the factory federal 90s.